<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		
	</head>
	<body>
		<table>
		  <tr>
			 <td><img src="" /></td>
			 <td colSpan="3">购物简易计算器</td>
		  </tr>
		  <tr>
			 <td>第一个数</td>
			 <td colSpan="3">
				 <input type="text" id="num1Id" />
			 </td>
		  </tr>
		  <tr>
			 <td>第二个数</td>
			 <td colSpan="3">
				 <input type="text" id="num2Id" />
			 </td>
		  </tr>
		  <tr>
			 <td>
				  <input type="button" value=" + " onclick="cal('+')"/>
			 </td>
			 <td>
				 <input type="button" value=" - " onclick="cal('-')"/>
			 </td>
			 <td>
				 <input type="button" value=" * " onclick="cal('*')"/>
			 </td>
			 <td>
				 <input type="button" value=" / " onclick="div()"/>
			 </td>
		  </tr>
		  <tr>
			 <td>计算结果</td>
			 <td colSpan="3">
				 <input  type="text" id="resultId" />
			 </td>
		  </tr>
	  </table>
	  
	  <script type="text/javascript">
	  	  function cal(type) {
	  		  var num1 = document.getElementById('num1Id').value;
	  		  var num2 = document.getElementById('num2Id').value;
	  		  //eval()   '3+5'   '3-5'  '3*5'
	  		  var result = eval(parseInt(num1) + type + parseInt(num2));
	  		  var resultObj = document.getElementById('resultId');
	  		  resultObj.value = result;
	  	  }
	  	  
	  	  //把变化的数据作为参数传递过来
	  	  function cal2(type) {
	  		  var num1 = document.getElementById('num1Id').value;
	  		  var num2 = document.getElementById('num2Id').value;
	  		  var result = 0;
	  		  switch (type){
	  			case '+':
	  				result = parseInt(num1) + parseInt(num2);
	  				break;
	  			case '-':
	  				result = parseInt(num1) - parseInt(num2);
	  				break;
	  			case '*':
	  				result = parseInt(num1) * parseInt(num2);
	  				break;
	  			case '/':
	  				result = parseInt(num1) / parseInt(num2);
	  				break;
	  			default:
	  				break;
	  		  }
	  		  var resultObj = document.getElementById('resultId');
	  		  resultObj.value = result;
	  	  }
	  	  
	  	  
	  	  function add() {
	  		  var num1 = document.getElementById('num1Id').value;
	  		  var num2 = document.getElementById('num2Id').value;
	  		  var result = parseInt(num1) + parseInt(num2);
	  		  var resultObj = document.getElementById('resultId');
	  		  resultObj.value = result;
	  	  }
	  	  
	  	  function sub() {
	  		  var num1 = document.getElementById('num1Id').value;
	  		  var num2 = document.getElementById('num2Id').value;
	  		  var result = parseInt(num1) - parseInt(num2);
	  		  var resultObj = document.getElementById('resultId');
	  		  resultObj.value = result;
	  	  }
	  	  
	  	  function mul() {
	  		  var num1 = document.getElementById('num1Id').value;
	  		  var num2 = document.getElementById('num2Id').value;
	  		  var result = parseInt(num1) * parseInt(num2);
	  		  var resultObj = document.getElementById('resultId');
	  		  resultObj.value = result;
	  	  }
	  	  
	  	  function div() {
	  		  var num1 = document.getElementById('num1Id').value;
	  		  var num2 = document.getElementById('num2Id').value;
	  		  var result = parseInt(num1) / parseInt(num2);
	  		  var resultObj = document.getElementById('resultId');
	  		  resultObj.value = result;
	  	  }
	  </script>
	</body>
</html>